The determination of the angular position of the crankshaft of internal combustion engines in motor vehicles is of great importance for the engine control, since, among other things, the point in time of fuel injection, and, in Otto engines, the point in time of ignition of the fuel/air mixture, in each cylinder is controlled as a function of the angular position of the crankshaft in such a way that optimum efficiency is ensured. For the determination of the angular position of the crankshaft, as a rule, incremental angle sensors are used that include an angle sensor for recording the passing by of angle marks on a signal-generating wheel that is rotatably fixed to the crankshaft. The angle marks are mostly made up of discrete teeth that radially protrude from the signal-generating disk, which, when they pass by, induce voltage signals in the sensor. These so-called tooth signals are transmitted to the engine control unit of the internal combustion engine and are evaluated there, in order to determine the current angular position of the crankshaft, and besides that, to determine the current rotary speed of the internal combustion engine via the signal frequency.
For the additional improvement of the engine control, it would be of advantage also to record accurately the angular position of the crankshaft when shutting down the internal combustion engine. If this were done, by having exact knowledge of the angular position of the crankshaft, one could substantially speed up the subsequent start of the internal combustion engine, which would be of advantage with respect to convenience and exhaust gas emissions. However, using the tooth signals transmitted at the present time by the angle sensor, the engine control unit is not in a position to fulfill this object because, when the internal combustion engine is shut down, before its final standstill, not all that rarely, there is a swinging motion, i.e. a reversal in the direction of rotation of the crankshaft happening one or more times, which prevents an exact determination of its angular position from the tooth signals.